Tubing for a combustion chamber

ABSTRACT

The tubing is formed with a developed surface so that the number of tubes passing out of the side edges of the rectangular surfaces of the funnel-shaped bottom is equal to the number of tubes passing out of the adjacent side edges of the trapezoidal surfaces. The angle of the tubes at entry into the four surfaces of the funnel-shaped bottom can also be the same as the tube angle in the vertical walls of the combustion chamber.

United States Patent 1 191 Brunner Sept. 3, 1974 [5 TUBING FOR A COMBUSTION CHAMBER 3,395,677 8/1968 Erandstetter ..122/235 [75] inventor: Alfred llirunner, Winterthur, FOREIGN PATENTS OR APPLICATIONS Swltzer and l,l63,303 9/1969 Great Britain 122 235 [73] Assignee: Sulzer' Brothers Ltd., Winterthur,

Swltzflland Primary Examiner-Kermeth W. Sprague [22] Fil d; M 22, 1973 Attorney, Agent, or FirmKenyon & Kenyon Reilly Carr & Chapin 21 App]. No.: 344,053

[30] Foreign Application Priority Data [57] ABSTRACT Mar. 17, 1972 Switzerland 4012/72 I h ing is f rmed with a eveloped surface so that the number of tubes passing out of the side edges of [52] US. Cl. 122/6 A, 122/235 A the rectangular surfaces of the funnel-shaped bottom [51] Int. CL. F22b 37/20 is equal to the number of tubes passing out of the ad- [58] Field of Search 122/DIG. 5, 6 A, 235 A, jacent side edges of the trapezoidal surfaces. The 122/235 C, 235 K angle of the tubes at entry into the four surfaces of the funnel-shaped bottom can also be the same as the tube [56] References Cited angle in the vertical walls of the combustion chamber.

UNITED STATES PATENTS Schroedter ..'l22/DIG. 5

4 Claims, 2 Drawing Figures PATENTED 35? 4 SIEETZWZ TUBING FOR A COMBUSTION CHANIBER This invention relates to tubing for a combustion chamber, particularly, a vertical combustion chamber.

Generally, the known vertical combustion chambers have been constructed with four vertical walls to define a rectangular cross-sectional shape and a funnelshaped bottom. This bottom has usually had two oppositely disposed rectangular surfaces inclined at an angle from a horizontal plane and two oppositely disposed vertically oriented trapezoidal surfaces. The combustion chamber walls have been formed of tubes inclined at the same angle from the horizontal and tightly welded together either directly or through the intermediary of bridges. These tubes have been extended into the surfaces of the funnel-shaped bottom and have been likewise tightly welded together therein.

It has already been proposed to have the tubes which extend from the combustion chamber walls into the funnel surfaces prolonged at approximately the same slope into the funnel surface. However, to do so would create a difficulty as an accumulation of tubes would occur in the region of the trapezoid side. In order to overcome this difficulty the individual tubes would have to be drawn out of the funnel surfaces, or would have to be conducted around parts of the funnel surfaces, or else would have to be shifted in some unsightly manner into the arrangement of tubing. All of these solutions would, however, obstruct rational fabrication.

Accordingly, it is an object of the invention to create a simple tubing arrangement in which the transition from the rectangular surfaces into the trapezoidal surfaces of a funnel-shaped bottom is smooth.

It is another object of the invention to provide a tubing plan in which the tubes emerging at the lower edges of the rectangular surfaces of a funnel-shaped bottom are directly and uniformly divided.

It is another object of the invention to provide a tubing plan from which tubing can be easily fabricated into a vertical combustion chamber having a funnel-shaped bottom.

Briefly, the invention provides a tubing for a combustion chamber as above which has a developed surface including a plurality of tubes inclined at an angle within four surfaces for forming the four walls of the combustion chamber. ln addition, the tubes extend on an angle into four other surfacesfor forming the rectangular and trapezoidal surfaces of the funnel-shaped bottom of the combustion chamber. The relationship of the various angles is such that the angle (a) of the rectangular surfaces to the horizontal is equal to the difference between 90 and twice the angle (a') at which the tubes extend into the four surfaces for the funnel-shaped bottom.

ln addition, at least a part of the tubes within each rectangular surface of the bottom are each bent to extend toward a lower edge of .the rectangular surface so that the number of tubes extending to a vertical edge of the surface is equal to the number of tubes extending to an adjacent edge of an adjacent trapezoidal surface.

The relationship of the angles of the rectangular surface to the horizontal and of the tubes in the surfaces teration of the directional path of at least a part of the tubes in the rectangular surfaces ensures an easy transition out of the rectangular surfaces into the trapezoidal surfaces.

In order to have the tubes emerge at the lower edges of the rectangular surfaces directly and uniformly divided, and have the tubes connected to collectors running parallel to the rectangle edges, the direction of the tubes in each rectangular surface is interrupted at that diagonal which intersects all the tubes entering into the rectangular surface.

It should be noted that this change of direction of the tubes at the diagonals causes the tube spacing to become changed. In addition, the bridges or other connecting elements between the tubes become somewhat wider after the change of direction than before the change of direction. The result of this is that there is an increase of the mean temperature in the adjacent rectangular part below the diagonal. However, because of the lower heat-load here and-the great elasticity of the wall formed of tubing, this is usually not of importance from the standpoint of strength.

Particularly simple conditions, favoring rational fabrication are obtained by making the angle or of the tubes in the funnel-shaped bottom surfaces equal to the slope-angle B of the tubes in the combustion chamber wall surfaces.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a development of tubing according to the invention for a combustion chamber. having a rectangular cross-section; and

FIG. 2 illustrates a corresponding development of the tubing for a combustion chamber which is square in plan view.

Referring to FIG. l,v the tubing for a combustion chamber has four surfaces for forming a front wall 1, side walls 2 and 4, and rear wall 3 of a combustion chamber. These surfaces are formed of a plurality of tubes 5 inclined at an angle of ,3 25 from the horizontal. The surfaces forming the front and rear walls 1, 3 are connected to a rectangular surface l0, 1] respectively, while the surfaces forming the side walls 2, 4, respectively adjoin equal-sided trapezoidal surfaces 12, 13 respectively at their base-lines 14, 15. The sides 16 to 19 of the trapezoidal surfaces l2, 13 are all of equal length, and equal to theshort sides 20 of the rectangular surfaces. The tubes, which are distributed uniformly over the perimeter, enter at an angle of a, for example, 20, into the rectangular and trapezoidal surfaces 10 to 13. The acute angle between the trapezoid sides 16 to 19 on the one hand and the base-lines 14, 15, on the other hand is designated a and is, for example, 50. In the assembled state, the angle a corresponds to the slope of the rectangular surfaces 10, 11 from the hori-.

zontal. The relationship between these angles a and a is expressed by the formula: or 2a.

This ensures that the tubes emerging from the sides l7, 19 of the trapezoidal surfaces l2, 13 can be continued without offsetting into the adjoining rectangular surfaces l1, 10 respectively.

The directional path of the tubes in each rectangular surface 10, 11 is bent or interrupted along a diagonal 30, 31. The angle of refraction is such that the tubes of each rectangular surface 10, 11 which, if extended without refraction, would run into the adjacent trapezoidal surface, are refracted to run into the lower horizontal edge of the rectangular surface. In order to determine the angle of refraction a straight line 33 is first drawn from the corner 32 of the trapezoidal surface 13 at the angle a of the tubes in the trapezoidal surface 13 to the diagonal 31 to determine a point 34. A straight line 36 from this point 34 to a point 35, corresponding to the point 32 but on the rectangular surface 11, determines the direction of the tubes in the rectangular surface 11 below the diagonal 31. This ensures that the required number of tubes are directed into the sides 18 of the trapezoidal surface 13 and, at the same time, ensures that the other tubes running into the rectangular surface 11 are distributed uniformly along the other side of the surface 11.

In the half of the rectangular surface 1 1 below the diagonal 31, the tube distribution is somewhat more spaced apart than in the upper half. However, as mentioned above, the stresses caused by heat-expansion are generally not considerable.

Referring to FIG. 2, wherein like reference characters indicate like parts as above, the surfaces forming the front and rear walls, as well as the side walls of the combustion chamber, are of equal width, so that the combustion chamber is square in plan view. In this case, the angle of slope B of the tubes in combustionchamber walls is equal to the entry angle a of the tubes in the rectangular and trapezoidal walls of FIG. 1. This permits a particularly simple and rational fabrication of the combustion chamber.

What is claimed is:

l. Tubing for a vertical combustion chamber comprising a plurality of interconnected tubes inclined at a first angle (B) from a horizontal plane within four surfaces defining a rectangular cross-sectional shape for forming four walls of the combustion chamber, said tubes extending on a second angle (a') from said four surfaces into four other surfaces for forming a funnel-shaped bottom including two oppositely disposed rectangular surfaces inclined at a third angle (a) from a horizontal plane and two oppositely disposed vertically oriented trapezoidal surfaces, said angles defining a relationship of a 2 (a), at least part of said tubes within each said rectangular surface being bent to extend toward a lower edge of said rectangular surface with the number of tubes extending to a vertical edge of said rectangular surface being equal to the number of tubes extending to an adjacent edge of an adjacent trapezoidal surface.

2. Tubing as set forth in claim 1 wherein said bent tubes in each respective rectangular surface are each bent at a point located on a diagonal of said rectangular surface transversing all of said tubes in said rectangular surface.

3. Tubing as set forth in claim 1 wherein said third angle (a') is equal to said second angle (,8).

4. Tubing as set forth in claim 1 wherein said third angle (a) is 20. 

1. Tubing for a vertical combustion chamber comprising a plurality of interconnected tubes inclined at a first angle ( Beta ) from a horizontal plane within four surfaces defining a rectangular cross-sectional shape for forming four walls of the combustion chamber, said tubes extending on a second angle ( Alpha '') from said four surfaces into four other surfaces for forming a funnel-shaped bottom including two oppositely disposed rectangular surfaces inclined at a third angle ( Alpha ) from a horizontal plane and two oppositely disposed vertically oriented trapezoidal surfaces, said angles defining a relationship of Alpha 90* - 2 ( Alpha ''), at least part of said tubes within each said rectangular surface being bent to extend toward a lower edge of said rectangular surface with the number of tubes extending to a vertical edge of said rectangular surface being equal to the number of tubes extending to an adjacent edge of an adjacent trapezoidal surface.
 2. Tubing as set forth in claim 1 wherein said bent tubes in each respective rectangular surface are each bent at a point located on a diagonal of said rectangular surface transversing all of said tubes in said rectangular surface.
 3. Tubing as set forth in claim 1 wherein said third angle ( Alpha '') is equal to said second angle ( Beta ).
 4. Tubing as set forth in claim 1 wherein said third angle ( Alpha '') is 20*. 